Silver-filled alumina membrane: metamaterial with hyperbolic dispersion and near-zero singularity

Hexagonal boron nitride (hBN) exhibits natural hyperbolic dispersion in the infrared (IR) wavelength spectrum. In particular, the hybridization of its hyperbolic phonon polaritons (HPPs) and surface plasmon resonances (SPRs) induced by metallic nanostructures is expected to serve as a new platform for novel light manipulation. In this study, the transmission properties of embedded hBN in metallic one-dimensional (1D) nanoslits were theoretically investigated using a rigorous coupled wave analysis method. Extraordinary optical transmission (EOT) was observed in the type-II Reststrahlen band, which was attributed to the hybridization of HPPs in hBN and SPRs in 1D nanoslits. The calculated electric field distributions indicated that the unique Fabry–Pérot-like resonance was induced by the hybridization of HPPs and SPRs in an embedded hBN cavity. The trajectory of the confined light was a zigzag owing to the hyperbolicity of hBN, and its resonance number depended primarily on the aspect ratio of the 1D nanoslit. Such an EOT is also independent of the slit width and incident angle of light. These findings can not only assist in the development of improved strategies for the extreme confinement of IR light but may also be applied to ultrathin optical filters, advanced photodetectors, and optical devices.

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Surface Plasmonic Sensors: Sensing Mechanism and Recent Applications

Sensors ◽

10.3390/s21165262 ◽

2021 ◽

Vol 21 (16) ◽

pp. 5262

Author(s):

Qilin Duan ◽

Yineng Liu ◽

Shanshan Chang ◽

Huanyang Chen ◽

Jin-hui Chen

Keyword(s):

Surface Plasmon Resonance ◽

Optical Fiber ◽

Surface Plasmon ◽

Optical Sensors ◽

Plasmon Resonance ◽

2D Materials ◽

Localized Surface Plasmon ◽

Plasmonic Sensors ◽

Hyperbolic Dispersion ◽

Challenges And Opportunities

Surface plasmonic sensors have been widely used in biology, chemistry, and environment monitoring. These sensors exhibit extraordinary sensitivity based on surface plasmon resonance (SPR) or localized surface plasmon resonance (LSPR) effects, and they have found commercial applications. In this review, we present recent progress in the field of surface plasmonic sensors, mainly in the configurations of planar metastructures and optical-fiber waveguides. In the metastructure platform, the optical sensors based on LSPR, hyperbolic dispersion, Fano resonance, and two-dimensional (2D) materials integration are introduced. The optical-fiber sensors integrated with LSPR/SPR structures and 2D materials are summarized. We also introduce the recent advances in quantum plasmonic sensing beyond the classical shot noise limit. The challenges and opportunities in this field are discussed.

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Nanoporous Alumina Membranes for Sugar Industry: An Investigation of Sintering Parameters Influence onUltrafiltration Performance

Sustainability ◽

10.3390/su13147593 ◽

2021 ◽

Vol 13 (14) ◽

pp. 7593

Author(s):

Farooq Khan Niazi ◽

Malik Adeel Umer ◽

Ashfaq Ahmed ◽

Muhammad Arslan Hafeez ◽

Zafar Khan ◽

...

Keyword(s):

Mechanical Strength ◽

Pore Size ◽

Sugar Industry ◽

Average Pore Size ◽

Research Work ◽

Homogeneous Distribution ◽

Alumina Membrane ◽

Average Pore ◽

Nanoporous Alumina ◽

Alumina Membranes

Ultrafiltration membranes offer a progressive and efficient means to filter out various process fluids. The prime factor influencing ultrafiltration to a great extent is the porosity of the membranes employed. Regarding membrane development, alumina membranes are extensively studied due to their uniform porosity and mechanical strength. The present research work is specifically aimed towards the investigation of nanoporous alumina membranes, as a function of sintering parameters, on ultrafiltration performance. Alumina membranes are fabricated by sintering at various temperatures ranging from 1200–1300 °C for different holding times between 5–15 h. The morphological analysis, conducted using Scanning electron microscopy (SEM), revealed a homogeneous distribution of pores throughout the surface and cross-section of the membranes developed. It was observed that an increase in the sintering temperature and time resulted in a gradual decrease in the average pore size. A sample with an optimal pore size of 73.65 nm achieved after sintering at 1250 °C for 15 h, was used for the evaluation of ultrafiltration performance. However, the best mechanical strength and highest stress-bearing ability were exhibited by the sample sintered at 1300 °C for 5 h, whereas the sample sintered at 1250 °C for 5 h displayed the highest strain in terms of compression. The selected alumina membrane sample demonstrated excellent performance in the ultrafiltration of sugarcane juice, compared to the other process liquids.

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Graphene-based tunable hyperbolic microcavity

Scientific Reports ◽

10.1038/s41598-020-80022-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Michał Dudek ◽

Rafał Kowerdziej ◽

Alessandro Pianelli ◽

Janusz Parka

Keyword(s):

Resonant Mode ◽

Transverse Magnetic ◽

Mid Infrared ◽

Nanophotonic Devices ◽

Wide Range ◽

Fabry Perot ◽

Hyperbolic Dispersion ◽

Low Threshold ◽

Infrared Frequencies ◽

Infrared Wave

AbstractGraphene-based hyperbolic metamaterials provide a unique scaffold for designing nanophotonic devices with active functionalities. In this work, we have theoretically demonstrated that the characteristics of a polarization-dependent tunable hyperbolic microcavity in the mid-infrared frequencies could be realized by modulating the thickness of the dielectric layers, and thus breaking periodicity in a graphene-based hyperbolic metamaterial stack. Transmission of the tunable microcavity shows a Fabry–Perot resonant mode with a Q-factor > 20, and a sixfold local enhancement of electric field intensity. It was found that by varying the gating voltage of graphene from 2 to 8 V, the device could be self-regulated with respect to both the intensity (up to 30%) and spectrum (up to 2.1 µm). In addition, the switching of the device was considered over a wide range of incident angles for both the transverse electric and transverse magnetic modes. Finally, numerical analysis indicated that a topological transition between elliptic and type II hyperbolic dispersion could be actively switched. The proposed scheme represents a remarkably versatile platform for the mid-infrared wave manipulation and may find applications in many multi-functional architectures, including ultra-sensitive filters, low-threshold lasers, and photonic chips.

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Gravity-Driven Separation of Oil/Water Mixture by Porous Ceramic Membranes with Desired Surface Wettability

Materials ◽

10.3390/ma14020457 ◽

2021 ◽

Vol 14 (2) ◽

pp. 457

Author(s):

Chunlei Ren ◽

Wufeng Chen ◽

Chusheng Chen ◽

Louis Winnubst ◽

Lifeng Yan

Keyword(s):

Porous Ceramic ◽

Ceramic Membranes ◽

Separation Performance ◽

Water Mixture ◽

Alumina Membrane ◽

Water Separation ◽

Alumina Membranes ◽

Oil Water Separation ◽

Gravity Driven ◽

Oil Water

Porous Al2O3 membranes were prepared through a phase-inversion tape casting/sintering method. The alumina membranes were embedded with finger-like pores perpendicular to the membrane surface. Bare alumina membranes are naturally hydrophilic and underwater oleophobic, while fluoroalkylsilane (FAS)-grafted membranes are hydrophobic and oleophilic. The coupling of FAS molecules on alumina surfaces was confirmed by Thermogravimetric Analysis and X-ray Photoelectron Spectroscopy measurements. The hydrophobic membranes exhibited desired thermal stability and were super durable when exposed to air. Both membranes can be used for gravity-driven oil/water separation, which is highly cost-effective. The as-calculated separation efficiency (R) was above 99% for the FAS-grafted alumina membrane. Due to the excellent oil/water separation performance and good chemical stability, the porous ceramic membranes display potential for practical applications.

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Heat Transfer Characteristics of Alumina Membrane Coated Activated Carbon with Core–Shell Structure

Industrial & Engineering Chemistry Research ◽

10.1021/ie303318t ◽

2013 ◽

Vol 52 (10) ◽

pp. 3653-3657 ◽

Cited By ~ 7

Author(s):

Fengqiu Chen ◽

Chenchen Cai ◽

Dang-guo Cheng ◽

Xiaoli Zhan

Keyword(s):

Heat Transfer ◽

Activated Carbon ◽

Shell Structure ◽

Core Shell ◽

Heat Transfer Characteristics ◽

Alumina Membrane ◽

Transfer Characteristics ◽

Core Shell Structure

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Fabrication of Photofunctional Nanoporous Membrane and Its Photoinactivation Effect of Vesicular Stomatitis Virus

Journal of Nanomaterials ◽

10.1155/2012/454507 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Kang-Kyun Wang ◽

Bong-Jin Kim ◽

Si-Hwan Ko ◽

Dong Hoon Choi ◽

Yong-Rok Kim

Keyword(s):

Vesicular Stomatitis Virus ◽

Photophysical Properties ◽

Antiviral Effect ◽

Nanosecond Laser ◽

Alumina Membrane ◽

Time Resolved ◽

Nanoporous Alumina ◽

Animal Virus ◽

Covalently Bonded ◽

Vesicular Stomatitis

Fabrication and photophysical study of photofunctional nanoporous alumina membrane (PNAM) were performed, and its application of photodynamic antimicrobial chemotherapy (PACT) was investigated. Nanoporous alumina membrane (NAM) was fabricated by two-step aluminium anodic oxidation process. Surface of the fabricated NAM was modified with organo-silane agent to induce covalent bonding between NAM and a photosensitizer (PtCP: [5,10,15-triphenyl-20-(4-methoxycarbonylphenyl)-porphyrin] platinum). PtCP was covalently bonded to the surface of the modified NAM by nucleophilic acyl substitution reaction process. The morphology and the photophysical properties of the fabricated PNAM were confirmed with field emission scanning electron microscope (FE-SEM), steady-state spectroscopies, and nanosecond laser-induced time-resolved spectroscopy. For the efficacy study of PNAM in PACT, an enveloped animal virus, vesicular stomatitis virus (VSV), was utilized as a target organism. Antiviral effect of the PNAM-PACT was measured by the extent of suppression of plaque-forming units (PFU) after the light irradiation. In the cultures inoculated with PACT-treated VSV, the suppression of PFU was prominent, which demonstrates that PNAM is a potential bio clean-up tool.

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Electron Magnetic Resonance Studies on Nanowire and Nanoparticle Arrays

MRS Proceedings ◽

10.1557/proc-1228-kk11-36 ◽

2009 ◽

Vol 1228 ◽

Author(s):

Osei K Amponsah ◽

Rakhim R. Rakhimov ◽

Yuri A. Barnakov ◽

Rosa A Lukaszew ◽

Jeffrey C Owrutsky ◽

...

Keyword(s):

Comparative Analysis ◽

Magnetic Resonance ◽

Electron Magnetic Resonance ◽

Superparamagnetic Nanoparticles ◽

Magnetic Nanowires ◽

Nanoparticle Arrays ◽

Alumina Membrane ◽

Magnetic Resonance Studies ◽

Magnetic Inclusions

AbstractArrays of magnetic nanowires and well-oriented chains of superparamagnetic nanoparticles were fabricated using polymer and alumina membrane templates. The systems were characterized by SQUID and studied by electron magnetic resonance methods. Comparative analysis of the obtained results for different geometries and sizes of the magnetic inclusions is presented.

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